The process Patent pertaining to the use of 3H-1,2-benzodithiole-3-one1,1- dioxide as a sulfur-transfer reagent in the synthesis of oligodeoxyribonucleoside phosphorothioates, filed by us in late 1989, has been issued by the U.S. Patent Office in March 1991. The reagent is now commercially available albeit at an outrageous price. To facilitate the accessibility of the reagent to academic laboratories (especially oligonucleotide synthesis core facilities ) Judith B. Regan and the P>I> have scaled up the preparation of the sulfurizing reagent to ca. 125 gr by a modified procedure with respect to that published in our laboratory. This improved procedure will be submitted in Organic Syntheses by late July. The conversion of oligonucleoside phosphorothioates into oligonucleoside phosphoroamidates (another class of oligonucleotide analogues) via an oxidative aminolysis is currently being investigated in our laboratory.